Participles (dalyviai) are used to describe a person or a thing in a way which is related to their actions or actions which are applied upon them. So it is used as an adjective as you pointed out in your message.
Every tense has its own dalyvis form and there are two types of dalyvis as well: active and passive.
Leaving all the grammatical terms aside, let's look at some examples.
Vyras, dirbantis šiame ofise, mėgsta krepšinį. (Vyras, kuris dirba šiame ofise, mėgsta krepšinį.)
A man, who is working at this office, likes basketball.
Vyras, dirbęs šiame ofise, mėgo krepšinį. (Vyras, kuris dirbo šiame ofise, mėgo krepšinį.)
A man, who was working at this office, liked basketball.
Vyras, dirbdavęs šiame ofise, mėgo krepšinį. (Vyras, kuris dirbdavo šiame ofise, mėgo krepšinį.)
A man, who used to work in this office, liked basketball.
Vyras, dirbsiantis šiame ofise, mėgsta krepšinį. (Vyras, kuris dirbs šiame ofise, mėgsta krepšinį.)
A man, who will be working in this office, likes basketball.
As you see, the man is/was/will be working at the office himself, so in this case we use active dalyvis. The sentences in the brackets mean exactly the same and you don't need to use dalyvis. The form of future dalyvis "dirbsintis" is very rarely used even by Lithuanians, so it will be logical not to learn it at all.
Grojama daina yra labai graži.
The song, which is (being) played, is very nice.
Nupiešta moteris atrodė labai jaunai.
The drawn women (The women who was drawn) looked very young.
In this case the song was played and the women was drawn, so the actions were applied to then. In this case we use passive dalyvis.
It might seem complicated, because it is and I can imagine that it can be pain in the backside to learn this kind of stuff, but I encourage you not to pay too much attention to this. You will get the feeling of it as you advance.